The invention pertains to a connecting link for a wiper system, in particular on a motor vehicle, to which the free end of a wiper arm attached to a wiper shaft driven back and forth and the free end of a control arm attached on a rotating axis are articulated at a distance from each other and with which a wiper blade is connected and can pivot in the direction toward the pane to be wiped.
Wiper systems for motor vehicles are known in which the wiper blade is moved back and forth essentially parallel to the pane itself and along the pane being wiped. In wiper systems of this kind, in addition to a wiper arm attached to a wiper shaft movable in pendulum fashion, there is a so-called control arm on a chassis-mounted, rotating axis. The free end of the wiper arm and the free end of the control arm are articulated with a coupling element, such that the two articulation points are kept at a distance from each other. The control arm can be aligned roughly parallel to the wiper arm, so that the coupling element completes a deformable parallelogram with the wiper arm and the control arm. It is also possible that the control arm intersects the wiper arm. The wiper blade belonging to the wiper system is attached pivotably at the coupling element about an axis running transverse to the longitudinal direction of the wiper blade.
From published German patent application No. 3,917,483 a connecting link of this kind is known, whose base element is designed as a single piece of sheet metal by punching and bending. From one back of the connecting link there are two side cheeks curved downward, that is, in the direction of the pane to be wiped, so that these side cheeks run at a distance from each other and parallel to each other. This region of the connecting element with the downward curved side cheeks thus forms a kind of closing clasp, and the wiper blade support bar is located between said side cheeks. The pivoting mount of the wiper blade at the connecting link is by means of a special threaded bolt which is extended through aligned holes in the side cheeks of the closing clasp and into the side cheeks of the wiper blade support bar and is secured with a nut.
This known connecting link has the significant disadvantage that it can only be used in connection with the specific wiper blades that have the necessary drill holes in the side walls of the wiper blade support bar. In addition, the threaded bolt that holds the wiper blade to pivot on the connecting link is exposed to large stresses. Therefore, the threaded bolt must be made of high quality material with corresponding strength, which results in correspondingly high costs. Another problem is that a necessary replacement of the wiper blade proves to be relatively cumbersome, and that the connecting link of sheet metal under current conditions does not exactly offer a pleasing sight. Finally, the latent possibility of injury during manual activities in the vicinity of the relatively sharp-edge connecting link must be pointed out.
From published German patent application No. 1,405,995 another connecting link of this kind of wiper system is known. As its base, this connecting link has a carrier manufactured from pressed synthetic resin. There are two articulated bolts attached to this carrier plate, which forms the back of the connecting link, and between the two articulated bolts there is a downward pointing closing clasp screwed on. Under certain circumstances, this connecting link does not have such a sharp edge, and thus the disadvantages of the connecting link attributable to the sharp edges from published German patent application No. 3,917,483 are not a factor. However, the other described features also apply to this connecting link.